I should probably preface this with, Copper is not cheap. That's why idle, old homes are raided for their copper. This ladder can probably be made more cheaply, as I did not shop around or look for any deals. I did notice, that 1/2" copper pipe fittings were more costly than 3/4" - so I built using 3/4". My total cost was $54.40.
Using the pipe cutter, cut the 5' stick of copper pipe into 4 pieces. Each piece should be 15" long, but your stick may be a smidge over or under 5' so it's good to measure and just divide by 4.
Using the pipe cutter, cut the 10' stick into 10 pieces. This means each stick should be 1' (12 inches) long. However, your 10' stick could be a smidge over or under 10' so it is good to measure and divide by 10.
Piece your ladder together! The long pieces are the top and bottom portions of ladder. The 1' sections are the ladder rungs and sides. The pipe should fit snuggly into the fittings, but if you don't like how they're mobile, you can always use some hot glue!
I heard ketchup is a good copper cleaner, I kind of like mine a bit dirty. I appreciate the aged look.